Replication of challenge viruses in mice immunized with the VN1203��NS1 virus.

aMice with lung virus load 10 TCID50/ml were classified as being protected.bThe virus titers are expressed as the mean log10 TCID50/ml��standard error (S.E.) from 6 animals. The limit of virus detection was 1.5 log10 TCID50/ml. Tissues where no virus was detected were defined as 1.5 log10 TCID50/ml for the calculation of the mean titer.Mice (6 animals per group) were administered i.n. one or two doses of the VN1203��NS1 virus (5.3 log10 TCID50/animal) three weeks apart and were challenged with homologous VN1203 (3.3 log10 TCID50/animal), or heterologous HK213 (3.2 log10 TCID50/animal), IND05 (2.2 log10 TCID50/animal) and Dk/Sing/97 (4.2 log10 TCID50/animal) viruses three weeks post each immunization. The decrease of the mean virus titers measured in the vaccinated group compared to the PBS treated group was significant in all the groups as determined by the Mann-Whitney U-test (p